Quick question about underclocking a Pentium 2

Discussion about old PC hardware.

Quick question about underclocking a Pentium 2

Postby retro games 100 » 2011-3-16 @ 19:34

Just double-checking something: can I run this thing [cpu world, pentium 2] with a 2x multi, @ 66 MHz bus speed = 133 MHz CPU clock speed? I'd like to see how slow a slot 1 PC can go. Thanks for any info.
User avatar
retro games 100
l33t
 
Posts: 4585
Joined: 2008-5-03 @ 17:46

Re: Quick question about underclocking a Pentium 2

Postby TheMAN » 2011-3-16 @ 19:38

I guess you don't have the CPU yet to try this? ;)

I don't think I got PIIs, only PIIIs... but they are in storage
my K6-3 is a 450 chip but underclocked to 400 (66*6)... works fine and probably is giving it excellent life
TheMAN
Oldbie
 
Posts: 839
Joined: 2011-2-12 @ 08:39

Re: Quick question about underclocking a Pentium 2

Postby leileilol » 2011-3-16 @ 19:58

I have this. I only got as low as 180mhz before hardlocking, haven't tried jumpering my way down further. DO I WANT TO!?!!?!11!?!
User avatar
leileilol
l33t++
 
Posts: 9457
Joined: 2006-12-16 @ 18:03

Re: Quick question about underclocking a Pentium 2

Postby Tetrium » 2011-3-16 @ 20:07

retro games 100 wrote:Just double-checking something: can I run this thing [cpu world, pentium 2] with a 2x multi, @ 66 MHz bus speed = 133 MHz CPU clock speed? I'd like to see how slow a slot 1 PC can go. Thanks for any info.

I "think" virtually all Klamaths are unlocked. I tried a 300Mhz Klamath and I could change the multi. Hope that helps!
User avatar
Tetrium
l33t++
 
Posts: 7640
Joined: 2010-1-27 @ 18:53
Location: Netherlands

Re: Quick question about underclocking a Pentium 2

Postby DonutKing » 2011-3-16 @ 21:30

My 266MHz Klamath was locked though. I don't have it any more so I couldn't tell you what date or stepping...
User avatar
DonutKing
Oldbie
 
Posts: 1790
Joined: 2008-1-03 @ 03:23
Location: Australia

Re: Quick question about underclocking a Pentium 2

Postby swaaye » 2011-3-16 @ 21:45

There's a thread on here somewhere that covered trying to find the unlocked vs. locked Klamath and Deschutes chips. Not all Klamaths are unlocked and some Deschutes ARE unlocked.
swaaye
Moderator
 
Posts: 7200
Joined: 2002-7-22 @ 21:24
Location: WI, USA

Re: Quick question about underclocking a Pentium 2

Postby Tetrium » 2011-3-17 @ 03:41

swaaye wrote:There's a thread on here somewhere that covered trying to find the unlocked vs. locked Klamath and Deschutes chips. Not all Klamaths are unlocked and some Deschutes ARE unlocked.

Hmm..maybe I should retest that Klamath? I remember having posted something about it in that unlocked thread but can't be arsed to look it up now, too tired lol
User avatar
Tetrium
l33t++
 
Posts: 7640
Joined: 2010-1-27 @ 18:53
Location: Netherlands

Re: Quick question about underclocking a Pentium 2

Postby mr_bigmouth_502 » 2011-3-17 @ 05:17

I think I once got a Pentium 2 of some sort running at 133MHz on a Slot 1 Pentium 3 board. It's been a few years, and I don't remember the specifics, but I think it was an ASUS board with a 440BX chipset. I don't even remember setting it to run like that either; it just sort of ran that way as soon as I plugged it in.
User avatar
mr_bigmouth_502
Oldbie
 
Posts: 1942
Joined: 2009-5-16 @ 19:43
Location: Canada

Re: Quick question about underclocking a Pentium 2

Postby retro games 100 » 2011-3-17 @ 06:59

I found the huge P2 unlocking thread on Vogons. It's here. Now, who knows the 5 digit CPU id codes, for the unlocked P2s? :wink: Because that thread is 192 replies long, and I don't have a spare 2 hours to read it ATM. :wink:
User avatar
retro games 100
l33t
 
Posts: 4585
Joined: 2008-5-03 @ 17:46

Re: Quick question about underclocking a Pentium 2

Postby Tetrium » 2011-3-17 @ 10:36

I don't think there is a comprehensive list, but I listed mine on page 4 or 5. Also the manufacturing date seems to be important, after week 30 1998 it seems none of the sought after sspec's are unlocked.
I only know about Deschutes (since I thought Klamath were always unlocked) and so far I know of only 2 Deschutes's speeds that seem to come in unlocked variants, 333Mhz and 400Mhz.

And about locked Klamath, I'm not sure yet this is the case. It is possible that the free multi on the unlocked variants work on every board!
User avatar
Tetrium
l33t++
 
Posts: 7640
Joined: 2010-1-27 @ 18:53
Location: Netherlands

Re: Quick question about underclocking a Pentium 2

Postby retro games 100 » 2011-3-17 @ 10:51

Thanks a lot for the info. I've just bought a P2 233 MHz, code SL2HD. When I receive it, I'll try it out in my i440BX slot 1 Asus P2B mobo, and set its jumpers to 2x multi and 66 MHz bus speed. Fingers crossed, it'll run the CPU @ 133 MHz. That would make this slot 1 machine run like a low/mid speed classic Pentium. Perhaps quite useful for games like Magic Carpet in SVGA mode?

Image
User avatar
retro games 100
l33t
 
Posts: 4585
Joined: 2008-5-03 @ 17:46

Re: Quick question about underclocking a Pentium 2

Postby bestemor » 2011-3-17 @ 23:23

Check out my postings on page 2:
http://www.vogons.org/viewtopic.php?t=20758&postdays=0&postorder=asc&highlight=sl2qf&start=20

Was able to get that 400mhz one down to 133mhz (effectively 150ish though).
User avatar
bestemor
Oldbie
 
Posts: 577
Joined: 2007-4-23 @ 22:09

Re: Quick question about underclocking a Pentium 2

Postby AdamP » 2011-3-18 @ 03:56

retro games 100 wrote:Now, who knows the 5 digit CPU id codes, for the unlocked P2s?


This is all in my thread, but to summarise:

I've tried the following Pentium IIs:

SL2U6 (400mhz Deschutes) - Locked
SL2S5 (333mhz Deschutes) - Locked
SL2KA (333mhz Deschutes) - Can be underclocked (No L2 cache below 200mhz though)
SL2HE (266mhz Klamath) - Can be underclocked (No L2 Cache below 166mhz)

The SL2HE runs okay at 133mhz. I haven't tried the SL2KA at 133mhz yet. I also have an SL2U7 (450mhz Deschutes), which I assume is locked (I can't remember whether I actually tested it or not).

Judging by this, the chances are that your SL2HD will be unlocked and run at 133mhz.
AdamP
Member
 
Posts: 358
Joined: 2009-8-21 @ 18:12
Location: England

Re: Quick question about underclocking a Pentium 2

Postby Tetrium » 2011-3-18 @ 11:15

Link to the other P2 unlock thread: viewtopic.php?t=24550&postdays=0&postorder=asc&start=20

My findings so far:
SL2QF (333Mhz Deschutes) - Unlocked
SL2S7 (400Mhz Deschutes) - Unlocked
SL2HE (266Mhz Klamath) - Unlocked

SL2U3 (350Mhz Deschutes) - Locked
SL2VY (300Mhz Deschutes) - Locked
Last edited by Tetrium on 2011-3-19 @ 03:41, edited 1 time in total.
User avatar
Tetrium
l33t++
 
Posts: 7640
Joined: 2010-1-27 @ 18:53
Location: Netherlands

Re: Quick question about underclocking a Pentium 2

Postby Tetrium » 2011-3-18 @ 11:45

ALL MULTIPLIER REPORTS COMBINED INTO A SINGLE POST

SL2HE (266mhz Klamath) - Can be underclocked (No L2 Cache below 166mhz) (AdamP)
SL2HE (266Mhz Klamath) - Unlocked (Tetrium)
SL2KA (333mhz Deschutes) - Can be underclocked (No L2 cache below 200mhz though) (AdamP)
SL2QF (333Mhz Deschutes) - Unlocked (Tetrium)
SL2S7 (400Mhz Deschutes) - Unlocked (Tetrium)

SL2VY (300Mhz Deschutes) - Locked (Tetrium)
SL2S5 (333mhz Deschutes) - Locked (AdamP)
SL2U3 (350Mhz Deschutes) - Locked (Tetrium)
SL2U6 (400mhz Deschutes) - Locked (AdamP)
Last edited by Tetrium on 2011-3-19 @ 03:41, edited 1 time in total.
User avatar
Tetrium
l33t++
 
Posts: 7640
Joined: 2010-1-27 @ 18:53
Location: Netherlands

Re: Quick question about underclocking a Pentium 2

Postby Malik » 2011-3-18 @ 12:12

My main interest in an underclockable (is there such a word? :pppt:) PII is that I can scale down to mimic a 486, and at the same time, will be able to load some demanding Win98-esque games when running at max non-overclocked stock speed - the 400MHz Deschutes specifically, for some higher-than-acceptable performance. And finally, all this interest, is to keep my running systems to a minimum.

But, unfortunately (or fortunately), due to my inability to find the said processors, I end up having 4 systems in my room. Including my actual 486 and actual PIII 450MHz.

But then again, I just don't know ...the 486... feel attached to it. Feel like nothing can actually replace a 486. Maybe it's all due to my inseparable nostalgic sentiments...

Crazy...me... :happyhappy:
User avatar
Malik
l33t
 
Posts: 2484
Joined: 2004-4-10 @ 14:37
Location: Malaysia

Re: Quick question about underclocking a Pentium 2

Postby leileilol » 2011-3-18 @ 12:32

it's the amibios, the pc speaker and the CPU name being numerical.
two of these not even a Pentium of equal speed can offer

though, cache disabling a p3 brings a nice 5.7 cpu score on speedsys. :)
User avatar
leileilol
l33t++
 
Posts: 9457
Joined: 2006-12-16 @ 18:03

Re: Quick question about underclocking a Pentium 2

Postby Malik » 2011-3-18 @ 12:51

leileilol wrote:it's the amibios, the pc speaker and the CPU name being numerical.
two of these not even a Pentium of equal speed can offer

though, cache disabling a p3 brings a nice 5.7 cpu score on speedsys. :)


Ah yes! And the numerical 66/33 or HI/LO LED display, and the TURBO button! How can I forget my Turbo button! :happyhappy:
User avatar
Malik
l33t
 
Posts: 2484
Joined: 2004-4-10 @ 14:37
Location: Malaysia

Re: Quick question about underclocking a Pentium 2

Postby Tetrium » 2011-3-18 @ 12:53

Malik wrote:My main interest in an underclockable (is there such a word? :pppt:) PII is that I can scale down to mimic a 486, and at the same time, will be able to load some demanding Win98-esque games when running at max non-overclocked stock speed - the 400MHz Deschutes specifically, for some higher-than-acceptable performance. And finally, all this interest, is to keep my running systems to a minimum.

But, unfortunately (or fortunately), due to my inability to find the said processors, I end up having 4 systems in my room. Including my actual 486 and actual PIII 450MHz.

But then again, I just don't know ...the 486... feel attached to it. Feel like nothing can actually replace a 486. Maybe it's all due to my inseparable nostalgic sentiments...

Crazy...me... :happyhappy:

Lol, same here.

For me anything with "Pentium" means old, while anything 486 and before sounds "ancient" and "useless" :P
But I think it's pretty cool to have a use for a 486 :)
User avatar
Tetrium
l33t++
 
Posts: 7640
Joined: 2010-1-27 @ 18:53
Location: Netherlands

Re: Quick question about underclocking a Pentium 2

Postby retro games 100 » 2011-3-18 @ 12:55

I have just received the P2 233 "SL2HD" CPU. I set the Asus P2B mobo's jumpers to "2x & 66", and the unsurprising Speedsys result can be seen below. This score seems to reflect what other people have discovered. Although the mobo's L2 cache is automatically deactivated when running this type of CPU with the multi set to 2x, the Speedsys score is higher than that of a real P1 133.

I wonder if it is impossible to get a slot 1 system to cover the speed range from a slow 486, through to a slow classic Pentium? The corresponding Speedsys score range would be about 20 to about 100. I appreciate that you can use a very fast Coppermine in a slot 1 mobo, and then deactivate its L1 cache in the BIOS, but this produces a very slow system, roughly equal to some kind of 386, with a corresponding Speedsys score of less than 10.

Image
User avatar
retro games 100
l33t
 
Posts: 4585
Joined: 2008-5-03 @ 17:46

Next

Return to General Old Hardware

Who is online

Users browsing this forum: bit, kaputnik, tayyare and 13 guests